LNP knew of Gibson's past: MP

SENIOR members of Queensland's Liberal National Party knew about MP David Gibson's past before he ran for parliament, a renegade MP says.

The member for Gympie resigned as chair of the powerful select ethics committee on Wednesday, saying he'd been subjected to a two-year campaign of intimidation and blackmail.

He's launched a defamation suit against political rival Scott Elms, who published details about his past.

Mr Gibson admits he faced unspecified charges in 1999 but no conviction was recorded.

When first selected as a Nationals candidate for the 2006 election, Mr Gibson didn't disclose the matter and Premier Campbell Newman says he found out about a number of claims three weeks ago.

But Palmer United Party MP Alex Douglas, who defected from the LNP in 2012, says the government needs to admit that it knew about Mr Gibson's past when he was preselected.

"A vast majority of the senior LNP members, but primarily former National Party people, and certainly most in the executive did know and it's come time to say exactly when they did know," he told ABC Radio on Thursday.

"I'm a former National party member and I was involved in the party and I remember when David Gibson was preselected ... and these issues were being raised at the time.

"To say they that didn't know what was being stated about David Gibson ... I believe, are false."

The premier's office noted Mr Gibson was not convicted of any offence.

Dr Douglas was dumped as chair of the ethics committee in November 2012 and later accused the premier of tampering with due process.

His replacement, the LNP's Peter Dowling, was forced to quit as chair in August 2013 over a sexting scandal.

Lockyer MP Ian Rickuss has been nominated to replace Mr Gibson as head of the select ethics committee.